The field of the disclosure relates generally to vehicles, and more particularly, to methods and systems for use in charging an electric vehicle.
With continuing sales of electric vehicles, such as battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV), there is a demand for charging facilities to facilitate recharging of the vehicles. Such charging facilities include an electric vehicle supply equipment (EVSE) unit that converts electrical energy received from a source of electrical power into a form that can be received by a vehicle for recharging the vehicle batteries. While commercial, dedicated charging stations exist, such commercial charging stations are still limited in number, and the potential exists that the number of electric vehicles in use will increase faster than available capacity of such commercial dedicated charging stations can increase.
At least some known electric vehicles are designed to receive charging power from EVSE units (also referred to as “EVSEs”) that are designed for residential use. However, the use of a residential EVSE unit may require modifications to a residential electrical system. In an effort to obviate the need for modification of residential electrical systems, at least some known electric vehicles incorporate EVSEs that are portable or are otherwise external to the electric vehicle (hereinafter collectively referred to as “portable EVSEs”), that enable the vehicle to receive charging currently directly from a residential electrical system, or from other relatively low-rated (e.g., non-industrial and/or non-commercial) electrical systems.
In at least some known electric vehicles that use portable EVSEs to receive power from power sources, the portable EVSE is configured (“rated”) to permit a level of current to pass through, that is drawn by a charger within the electric vehicle, wherein the power draw may exceed the capacity of a typical residential wall outlet. Accordingly, an optimal recharging environment includes a dedicated residential electrical circuit that is rated at or above the rating of the portable EVSE unit and/or the charger in the vehicle. However, a dedicated residential circuit rated to supply sufficient current to charge the vehicle may not be available. Furthermore, even if the residential electrical system includes a power supply circuit that is rated at or above the rating of the EVSE unit or the maximum draw of the vehicle charger, if the EVSE unit shares the circuit with another load, such as a television or a refrigerator, it is possible under some conditions that the total demand may exceed the capacity or breaker limit of the electrical circuit, causing the breaker associated with the electrical circuit to trip, interrupting charging of the vehicle and inconveniencing the vehicle owner.